Ratio - situations in which we need to compare two quantities in terms of their ratio. (e.g., if Munna weighs 40 Kg. and Munni weighs 50 Kg., find the ratio of their weights.)
Children upto the age of 10 would usually come across the first two models. The third model is the inverse of the 'scale' model of multiplication, and is more difficult for the usuaI 10-yeardld to grasp.
To understand what division is, children need to be given plenty of examples of the first two types of situations in different contexts, all of which are familiar to them.